Disallow applying patches when git tree is dirty

git_cl.py

Index: git_cl.py
diff --git a/git_cl.py b/git_cl.py
index 4edb6a0af8e1ee834f7f8305e92e435a3c1f9cee..eaafa01398df6c8bbd8473dcfa304e2b0f131855 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -2401,6 +2401,9 @@ def CMDpatch(parser, args):
     return 1
   issue_arg = args[0]
 
+  if is_dirty_git_tree('patch'):
+    return 1
+
   # TODO(maruel): Use apply_issue.py
   # TODO(ukai): use gerrit-cherry-pick for gerrit repository?
 
@@ -2464,6 +2467,7 @@ def PatchIssue(issue_arg, reject, nocommit, directory):
     subprocess2.check_call(cmd, env=GetNoGitPagerEnv(),
                            stdin=patch_data, stdout=subprocess2.VOID)
   except subprocess2.CalledProcessError:
+    RunGit(['reset', '--hard'])

[Sam Clegg, 2015/02/02 17:43:18]

I find this a little scary. Perhaps skip this and update the line below to be
"Failed to apply the patch (use git reset --hard to cleanup remnants)'.  I'm not
adamant about this I just have a fear of scripts that do "reset --hard" at any
point.  If you are sure this is not going to burn anyone I'm OK with leaving it
in as I think it is technically correct.

If you do choose to leave then in then perhaps assert(!is_dirty_git_tree) at
start of PatchIssue in case anyone else tries to call it later?

[wychen, 2015/02/03 02:33:44]

Done.

     DieWithError('Failed to apply the patch')
 
   # If we had an issue, commit the current state and register the issue.
@@ -2769,6 +2773,15 @@ def CMDset_close(parser, args):
 
 def CMDdiff(parser, args):
   """shows differences between local tree and last upload."""
+
+  # Uncommitted (staged and unstaged) changes will be destroyed by
+  # "git reset --hard" if there are merging conflicts in PatchIssue().
+  # Staged changes would be committed along with the patch from last
+  # upload, hence counted toward the "last upload" side in the final
+  # diff output, and this is not what we want.
+  if is_dirty_git_tree('diff'):
+    return 1
+
   cl = Changelist()
   issue = cl.GetIssue()
   branch = cl.GetBranch()